Asaki Nishikawa Rips 4:07.67 Personal Best To Rattle 400 IM Rankings At Japan Open

2025 JAPAN OPEN

• Friday, November 28th – Sunday, November 30th
• Tokyo Aquatics Center
• LCM (50m)
• Meet Central
• SwimSwam Preview
• Day 1 Recap
• Live Results
• Livestream

Day two of the 2025 Japan Open unfolded tonight from the Tokyo Aquatics Center with more impressive performances produced by both domestic athletes and those visiting from Australia, Canada and beyond.

World Junior record holder Shin Ohashi followed up his 100m breast victory from night one with a powerful swim in the 50m breast for his second gold.

Ohashi ripped a mark of 27.01 to land atop the podium, producing a new Japanese National High School record in the process.

Reo Okura was next to the wall in 27.16 followed by Toshinari Yanagisawa who clocked 27.30.

16-year-old Ohashi has been on a tear this year, ripping new WJR’s of 58.94 and 2:06.91 in the boys’ 100m and 200m breaststroke events, respectively. He landed on the podium in all three breaststroke distances at this year’s World Junior Championships, claiming 50m breast bronze, 100m breast silver and 200m breast silver.

His time tonight renders him the 4th-swiftest performer in the world at the moment.

The women’s 50m breast saw its top two finishers separated in age by 18 years, as 34-year-old veteran Satomi Suzuki got to the wall first ahead of 16-year-old Aussie Sienna Toohey.

Suzuki registered a gold medal-worthy outing of 30.66 and Toohey was also sub-31 seconds in a result of 30.99. Sophie Angus rounded out the podium in 31.25 to give Canada the bronze.

Suzuki remains Japan’s national record holder in this sprint, owning a lifetime best of 30.10 from 2023. Toohey’s outing tonight checks in as the teen’s 3rd-best effort of all time, with her PB standing pat at 30.73 from earlier this year.

Suzuki, a multi-medalist at the 2012 Olympic Games, now sits 3rd in the world in the women’s 50m breaststroke event.

18-year-old Tatsuya Murasa put up a head-turning swim en route to winning the men’s 400m freestyle.

The teen fired off a lifetime best of 3:46.73 to keep Aussie Benjamin Goedemans at bay, with Goedemans hitting 3:47.13 as the silver medalist.

Kazushi Imafuku earned 3rd place tonight in 3:49.33.

Murasa, the 2025 World Championships bronze medalist in the 200m free, previously held a career-swiftest outing of 3:37.63 in this longer event. That time was established at the Japanese National Sports Festival this past September.

However, his 3:46.73 time tonight bumps him up the all-time Japanese performers list to now rank as the 5th-quickest in history.

Top 5 Japanese Men’s LCM 400 Freestyle Performers All-Time

1. Kosuke Hagino – 3:43.90, 2014
2. Takeshi Matsuda – 3:44.99, 2008
3. Kaito Tabuchi – 3:46.22, 2025
4. Naito Ehara – 3:46.65, 2018
5. Tatsuya Murasa – 3:46.73, 2025

Furthermore, Murasa now ranks 3rd in the world this season.

The all-time Japanese rankings were also shaken up in the men’s 400m IM final, courtesy of Asaki Nishikawa.

The 19-year-old turned in a monster effort of 4:07.67 to get the job done, logging the sole time of the field under the 4:10 barrier.

Australia’s William Petric posted 4:10.27, a new lifetime best by more than a second, as the runner-up. Yumeki Kojima, the reigning World Junior Championships bronze medalist, was just over a second behind in 4:11.49 to round out tonight’s podium.

Nishikawa’s previous PB entering this competition rested at the 4:09.26 posted this fall at the Japanese Student Championships, so the teen hacked well over a second off that result to break through.

His time would have beaten teammate and Olympic silver medalist Tomoyuki Matsushita‘s effort of 4:08.32 clocked for silver at this year’s World Championships behind French champion Leon Marchand.

The Japanese men are on a roll in this 4IM event, with three of the top five performers in history having registered their personal bests in 2025. Additionally, Nishikawa now ranks 13th among the all-time worldwide performers.

Top 5 Japanese Men’s LCM 400 IM Performers All-Time

1. Kosuke Hagino – 4:06.05, 2016
2. Daiya Seto – 4:06.09, 2020
3. Tomoyuki Matsushita – 4:07.21, 2025
4. Asaki Nishikawa – 4:07.67, 2025
5. Yumeki Kojima – 4:09.38, 2025

Nishikawa now checks in as the #2 performer in the world this season.

Hong Kong’s Siobhan Haughey dominated the women’s 100m free this evening, beating the pack by over a second.

Haughey struck gold in 53.04, with the next-closest competitor represented by Nagisa Ikemoto who touched in 54.11. Abbey Webb of Australia also landed on the podium in 54.43.

Additional racers included Taylor Ruck of Canada who settled for 4th in 54.64 and three-time Olympian Rikako Ikee who placed 7th in 55.35.

As for 28-year-old Haughey, the Olympic multi-medalist has already been as fast as 52.89 this season, a time she notched en route to winning gold in the event at this month’s Chinese National Games to rank #1 in the world right now.

A handful of men dipped under the 49-second barrier in the men’s version of the 100m free, led by Australian Kai Taylor.

22-year-old Taylor, a two-time relay medalist from last year’s Olympic Games, stopped the clock at 48.36 to narrowly defeat last night’s 200m free victor Edward Sommerville.

Sommerveille settled for silver here in 48.37 and Olympian Matt Temple got on the board with bronze in 48.61.

Canada’s Ruslan Gaziev placed 4th in 48.64 and another Aussie, Marcus Da Silva, captured a time of 48.97 for 5th place.

Additional Notes

• Molly Walker of Australia upgraded her bronze from last night’s 800m free to gold this evening in the 400m. Walker punched a result of 4:08.15 to hold off open water ace Ichika Kajimoto who settled for silver in 4:09.52. Versatile Brittany Castelluzzo bagged the bronze in 4:10.41. Walker’s effort represents just the 2nd performance of her career under the 4:10 barrier. She owns a PB of 4:07.22 from this year’s U.S. Summer Championships.
• 22-year-old Jenna Forrester of Australia was too quick to catch in the women’s 400m IM, leading wire-to-wire to ultimately touch in a time of 4:38.75. That held a healthy advantage over Waka Kobori who was next to the wall in 4:39.60 followed by Shuna Sasaki‘s time of 4:42.21. Forrester is the reigning World Championships silver medalist in this event, having punched a time of 4:33.26 to tie Japan’s Mio Narita this year in Singapore.
• University of Tennessee’s Mizuki Hirai scored the women’s 50m fly gold in 25.99, within striking distance of her best-ever outing of 25.63 from this year’s World Championships. Ruck was a hair behind this evening in 26.05 and Ai Soma bagged the bronze in 26.19. Hirai’s performance sneaks her into the top 5 list for the season.

• The men’s 50m butterfly saw 23-year-old Ben Armbruster get it done for gold in a time of 23.10. That represented the 5th swiftest performance of his career, one that boasts a lifetime best of 23.00 from this summer. Yuya Tanaka was the silver medalist this evening in 23.45 and Kota Ichikawa rounded out the podium in 23.57. Armbruster now ranks as the #2 performer this season.

• Aimi Nagaoka was the top women’s 200m backstroker tonight, registering 2:10.55 to top the podium. Narita touched next in 2:10.74 and Kyoka Sawa also landed on the podium in 2:11.29, good enough for bronze.
• Hidekazu Takehara doubled up on his 100m back victory from night one with another gold in the men’s edition of the 200m back. Takehara turned in a time of 1:56.11 to defeat the field by over a second. Kodai Nishiono secured silver in 1:57.22 and Daiki Yanagawa bagged the bronze in 1:59.07. Takehara ranks #1 in the world as a result of the season-best 1:55.50 he notched at September’s Japanese Intercollegiate Swimming Championships.